Consolidated Statements of Member's/Stockholders' Equity Consolidated Statements of Member's/Stockholders' Equity (Parenthetical) $ in Millions	Dec. 31, 2017 USD ($)
Member Units \| Accounting Standards Update 2014-09
Cumulative effect of new accounting, tax	$ 3

Cumulative Effect of New Accounting Principle in Period of Adoption, Tax

No definition available.

Name:	lvlt_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoptionTax
Namespace Prefix:	lvlt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant